A reliable power supply of the future

Project state

Started

Structural changes of the grid as a consequence of the energy transition and effects on the security of supply. | Image: Universität Wuppertal

The energy transition is causing a transformation of the German energy supply system. The effects are: more smart grid technologies, renewable energy generation and decentralised storage systems. In the future, the load behaviour of the consumers will affect the security of supply. Distribution networks will face serious changes. There will be new challenges and changing frame conditions. These include, for example, ancillary services and the ability to form isolated grids. This affects rural grids in particular, where consumption is low and feed-in based on wind, photovoltaics and biomass is high.

It is not clear how influencing factors will affect the reliability of supply in the future. The number of potential sources of defects in the distribution networks will rise in the future. Why is that the case? Smart grid technologies will help integrate decentralised energy generation systems in such a way that grid expansion is minimised. The failure probability of a system rises with the amount of technology required. Furthermore, large power plants will be replaced by a multitude of decentralised energy conversion systems. These systems must then provide ancillary services taking into account aspects of local security of supply. On the other hand, future distribution network automation in conjunction with decentralised energy conversion systems, controllable loads and storage systems can positively affect the security of supply. This is the case when additional functions such as the ability of certain grid segments to form isolated grids can be utilised, for example.

Ancillary services rendered by renewable energies

The research project “Auswirkungen der Energiewende auf die Versorgungszuverlässigkeit von Verteilungsnetzen” (Effects of the energy transition on the security of supply of distribution networks, AEwene) aims to contribute to determining the expected future security of supply of German distribution networks. To this end, researchers at the University of Wuppertal – in co-operation with Siemens – are developing reliability models for decentralised feed-in from renewable energy sources. The focus is on photovoltaic installations in the medium and low voltage grids, wind turbines and controllable cogeneration plants based on biomass and biogas. They also take into account storage systems and future load applications because they can provide ancillary services. A major element of the project is to map out the reliability of smart grid technologies in different voltage levels. As a result, the interaction between decentralised suppliers, storage systems, loads and smart grid technologies can be simulated in the future voltage field in distribution grids. In order to represent the behaviour of future components in the grid and consider them in terms of their reliability, the engineers are designing models for photovoltaic systems, wind turbines, biomass plants, cogeneration and hydropower plants, as well as storage and smart grid technologies. To this end, they are analysing the failure behaviour of the individual components of the suppliers (inverters, generators, rotors, transmission components, safety devices, etc.), storage systems and smart grid technologies, and are applying them to Markov models of the individual components. The models of the individual components are then combined to form a holistic model of the suppliers and smart grid technologies.

With the help of the developed and implemented models, it is possible to simulate the reliability of future grids and quantify whether the security of supply will improve or deteriorate. They are also investigating the extent to which distribution networks can reliably provide ancillary services as required in the future from out of the distribution grid. To this end, the developed models are applied in numerous representative, real grids of different distribution grid operators and compared using conventional calculus of reliability methods. Distribution gird operators would then be enabled to plan and build future distribution grids that are adapted to the energy transition with the desired level of security of supply.